煤层工作面开采会引起底板应力场的重新分布,造成煤岩体的变形和破坏,而综放顶煤开采初期工作面底板受力是判断煤岩体是否产生变形、破坏趋势的关键时期,了解该区岩体应力特征的变化,对煤层的安全开采具有重要意义.为研究厚煤层顶煤综采初期工作面切眼底板岩层应力变化特征,以山西某煤矿13505工作面为研究对象,采用分布式光纤应变测试技术动态监测了工作面切眼底板岩层应力分布,分析了综放开采初期厚煤层工作面底板应力特征分析.结果表明,光纤应变分布的变化与地层岩性吻合良好.钻孔光纤控制区内泥岩、灰岩、细砂岩的光纤应变均为压应变,说明采动影响下的工作面底板整体受压;断层结构限制了采动应力对岩层横向影响的程度和幅度;工作面切眼底板外侧的砂质泥岩和细砂岩的光纤总应变变化不明显,采动应力滞后影响距离为35 m.
Characteristics Analysis of Stress on the Bottom Plate of Thick Coal Seam Working Face in the Early Stage of Fully Mechanized Top Coal Mining
The mining of coal seam working face will cause the redistribution of stress field on the floor,resulting in deformation and damage of coal and rock mass. The stress on the bottom of the working face in the early stage of comprehensive top coal caving mining is a key period to determine whether the coal and rock mass have deformation and damage trends. Understanding the changes in the stress characteristics of the rock mass in this area is of great significance for the safe mining of coal seams. In order to study the stress variation characteristics of the shale layer at the bottom of the coal seam during the initial stage of fully mechanized mining in thick coal seams,the 13505 working face of a coal mine in Shanxi Province was taken as the research object. Distributed fiber optic strain testing technology was used to dynamically monitor the stress distribution of the shale layer at the bottom of the coal seam during the initial stage of fully mechanized mining in thick coal seams,and the stress characteristics of the bottom plate of the working face were analyzed. The results indicate that the changes in fiber optic strain distribution are in good agreement with the lithology of the formation. The fiber optic strain of mudstone,limestone,and fine sandstone in the drilling fiber optic control area is compressive strain,indicating that the working face floor is under overall compression under the influence of mining. The fault structure limits the degree and magnitude of the lateral influence of mining stress on rock layers. The total strain of the optical fiber in the sandy mudstone and fine sandstone on the outer side of the eye plate of the working face is not significantly changed,and the hysteresis effect distance of the mining stress is 35 meters.
stress on the bottomfully mechanized mining facethick coal seamdistributed strain optical fiber
万方数据
维普
